Clamshell coupling system and method

ABSTRACT

A clamshell coupling for a conduit system is provided. The clamshell coupling may comprise at least one longitudinal housing having first and second ends adapted to receive sections of conduit. A restraint system may be disposed on an interior surface of the longitudinal housing. The restraint system operates to actively engage at least one conduit and resist a longitudinal load between the clamshell coupling and the conduit. A coupling system may be used to secure the longitudinal housings to the tubular members.

RELATED APPLICATION

[0001] The present application claims the benefit of U.S. ProvisionalApplication Ser. No. 60/118,579, entitled Clamshell Coupling, filed Feb.5, 1999 (Attorney Docket 065571.0106). The present application isrelated to co-pending U.S. patent application Ser. No. 09/379,550,entitled Radial Conduit Coupling System and Method, filed Aug. 23, 1999(Attorney Docket 065571.0102).

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates generally to pipe fittings, andmore particularly to a clamshell coupling system and method.

BACKGROUND OF THE INVENTION

[0003] Conduit systems are used in a number of industries andapplications to form a passage(s) for communicating a media(s). Forexample, conduit systems are utilized in water and sewage plumbingsystems; electrical wire and optic fiber conduit systems; hydraulic andpneumatic systems; as well as other devices and systems. The conduitsystem generally comprises a number of pipes that are connectedtogether, or assembled, to form the conduit system. The pipe is oftenconstructed from a plastic, such as rigid or plasticized polyvinylchloride (PVC), and polyethylene. The pipe may be rigid or flexible, andis generally formed in relatively short lengths that must be joinedtogether. In many applications a pipe coupling is used to join thepipes. Pipe couplings can be permanent or detachable. Conventional pipecouplings have several disadvantages. Many piping systems are “welded”together through a process called electro-fusion. This is an expensiveand time consuming operation with many drawbacks. For instance, themelting points associated with pipes of different manufacturers may varyconsiderably thereby hindering the welding operation. Accordingly,skilled artisans are required to assemble piping components and theprocess must be adjusted continually as ambient temperature changes.

[0004] Conventional pipe couplings are often difficult to assemble andprone to failure. In addition, many do not form a tight seal between thepipe interior and ambient environment, thereby allowing the media toescape to the outside environment, or allowing the outside environmentto contaminate the media. In general, conventional pipe couplings aredifficult to install and assemble, thereby requiring expensive skilledartisans to construct the conduit system. Conduit systems provide anenvironmentally secure and protective passage for routing optic fibersfrom one location to another.

[0005] In one method of installation, a trench is dug and the pipe isinserted into the trench. A coupling may be used to attach additionalpipes to the buried pipe and the construction process continues. In manyinstances, an obstacle, such as a roadway or the like, prevents a trenchfrom being dug. In these instances, a small passage, or borehole may beexcavated under the obstacle and the pipes and the associated couplingsare pulled through the passage. The pulling action may create alongitudinal tension load between the couplings and their associatedpipes. The pipes may be separated from their associated couplings whenunder an excessive longitudinal tension load. In many situations, thepipes and/or couplings are also rotated and pulled in order to get thepipes through a restricted passage. Rotating the pipes places arotational load on the couplings and vice versa. The rotational load mayalso cause the tubular conduit to separate from the coupling.

SUMMARY OF THE INVENTION

[0006] Accordingly, a need has arisen in the art for an improvedcoupling. The present invention provides a clamshell coupling thatsubstantially reduces or eliminates problems associated with priorsystems and methods.

[0007] In accordance with one embodiment of the present invention, acoupling comprises at least one semi-tubular, longitudinal housing,having first and second ends which may be adapted to receive at leastone section of conduit. The housing may include a first indented regionforming a locking lug upon the exterior diameter of the housing. In oneembodiment, a second semi-tubular, longitudinal housing, complimentaryto the first housing, may be provided, having at least a second indentedregion forming a second locking lug upon an exterior diameter of thesecond housing. A locking mechanism including first and secondprotrusions which cooperate with the first and second locking lugs tocouple the first and second housings at a first longitudinal joint, mayalso be provided.

[0008] In a particular embodiment, a hinge operable to couple the firstand second housings at a second longitudinal joint may also be provided.In another embodiment, third a fourth indented regions associated withthe first and second housings, respectively, may form third and fourthlocking lugs on respective exterior diameters of the first and secondhousings. In this embodiment, a second locking mechanism having thirdand fourth protrusions which cooperate with the third and fourth lockinglugs, respectively, to couple the first and second housings at a secondlongitudinal joint, may also be provided.

[0009] A restraint system may also be provided at an interior diameterof the first housing. In one embodiment, the restraint system mayinclude at least one semi-circular insert disposed along the interiordiameter. The insert may include a plurality of gripping teeth operableto engage the conduit when the conduit coupling is in an assembledposition. In another embodiment, the restraint system may include aplurality of spikes extending from the interior diameter and operable toengage the conduit when the coupling is in an assembled position. In yetanother embodiment, the restraint system may include at least onesemi-circular gasket protruding from a notched opening within theinterior diameter.

[0010] In a particular embodiment, the gripping teeth and/or spikes mayextend toward a central portion of the interior diameter, and form anangle greater than 5 degrees with respect to a longitudinal central axisof the conduit coupling. In another embodiment, the gripping teethand/or spikes may include respective points which extend, approximatelyperpendicular to an axial central axis of the coupling. In still anotherembodiment, the points may extend toward an axial midpoint of theconduit coupling.

[0011] The present invention provides several technical advantages. Forexample, the coupling can resist very high longitudinal tension loads,as well as rotational loads. Thus, the coupling may be used in high loadapplications without the conduits becoming separated from the coupling.Accordingly, the cost and expense associated with constructing a conduitsystem are reduced.

[0012] Another technical advantage of the present invention is that theclamshell coupling is generally constructed from plastic materials thatwill not corrode. Accordingly, the operational life of the conduitsystem is longer, and the cost of the conduit system is reduced.

[0013] Still another technical advantage of the present invention isthat the clamshell coupling can maintain a tight environmental sealbetween the clamshell coupling and the tubular members. Accordingly, themedia within the conduit system cannot easily leak to the outsideenvironment, and the outside environment cannot easily contaminate themedia.

[0014] Yet another advantage is the couplings low profile that makes iteasier to install in tight spaces and causes lower friction when pullingthrough a bore hole.

[0015] A further technical advantage of the present invention is thatthe clamshell coupling is easy to install and remove. Accordingly, thetime and expense associated with constructing the conduit system arereduced.

[0016] Other technical advantages will be readily apparent to oneskilled in the art from the following figures, descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] For a more complete understanding of the present invention andthe advantages thereof, reference is now made to the followingdescription taken in conjunction with the accompanying drawings, whereinlike reference numerals represent like features, in which:

[0018]FIG. 1 is a schematic drawing in section illustrating a conduitsystem using a clamshell couplings in an optic fiber communicationsystem in accordance with the present invention;

[0019]FIG. 2A is an exploded orthographic drawing illustrating aclamshell coupling in accordance with the present invention;

[0020]FIG. 2B is a schematic drawing illustrating a cross section of aportion of the clamshell coupling of FIG. 2A taken along lines 2B-2B, inaccordance with the present invention;

[0021]FIG. 2C is a schematic drawing in section, illustrating a partialcross-section of an insert, in accordance with one aspect of the presentinvention.

[0022]FIG. 2D is a schematic drawing in section, illustrating a partialcross-section of semi-circular rib, in accordance with another aspect ofthe present invention.

[0023]FIG. 2E is a schematic drawing illustrating an assembled end viewof the clamshell coupling of FIG. 2A in accordance with the presentinvention;

[0024]FIG. 3A is an orthographic drawing of a clamshell coupling inaccordance with another embodiment of the present invention;

[0025]FIG. 3B is a schematic drawing in section, illustrating a spike,in accordance with one aspect of the present invention; and

[0026]FIG. 4 is an orthographic drawing of a clamshell coupling inaccordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0027] The preferred embodiments of the present invention and itsadvantages are best understood by referring now in more detail to FIGS.1-4 of the drawings, in which like numerals refer to like parts.

[0028] Throughout this description, the descriptive terms “originating”and “destination” are used to illustrate the operation of the variouscomponents. In practice, the components described as “originating” and“destination” typically performs originating and destination operationssimultaneously. It will therefore be appreciated that the terms“originating” and “destination” are not intended to limit the scope ofthe present invention.

[0029]FIG. 1 is a schematic drawing in section illustrating a conduitsystem 10 incorporating a clamshell coupling 12. Conduit system 10 isillustrated as part of an optic fiber communication system 14 used in atelecommunication system 16. Clamshell coupling 12 may also be used invarious other conduit systems that are used to communicate various othersuitable medias and material. For example, conduit system 10 may be usedfor communicating various fluids (liquids and/or gases), wiring such ascopper wire, twisted pairs, coaxial cable, and the like.

[0030] Telecommunication system 16 comprises a number of communicationdevices 18 a, such as telephones, that are coupled to an originatingswitching system 20 a. The originating switching system 20 a is coupledto an originating point of the optic fiber communication system 14. Adestination switching system 20 b is coupled to a destination point ofthe optic fiber communication system 14. The destination switchingsystem 20 b is coupled to a number of communication devices 18 b.

[0031] The switching systems 20 a and 20 b operate to routecommunication signals, i.e., telephone calls, from the originatingcommunication devices 18 a to the appropriate destination communicationdevices 18 b. The optic fiber communication system 14 allows thecommunication signals to be transmitted between the originatingswitching system 20 a and the destination switching system 20 b at veryhigh speeds and with a very large bandwidth, as compared to wirelinesystems. The optic fiber communication system 14 comprises at least oneoptic fiber 22 coupled between an originating optical interface 24 a anda destination optical interface 24 b. The optical interfaces 24 a and 24b operate to convert electronic communication signals 26 into opticalcommunication signals 28, and conversely, convert optical communicationsignals 28 into electronic communication signals 26.

[0032] In practice, a phone call may be placed from an originatingcommunication device 18 a to a destination communication device 18 b.The originating switching system 20 a receives the electroniccommunication signal 26 from the originating communication device 18 aand routes the electronic communication signal 26 to the originatingoptical interface 24 a. The originating optical interface 24 a convertsthe electronic communication signal 26 into an optical communicationsignal 28 that is transmitted through the optic fiber 22 to thedestination optical interface 24 b. The optical interface 24 b thenconverts the optical communication signal 28 into the electroniccommunication signal 26 that is routed to the destination switchingsystem 20 b. The destination switching system 20 b then routes theelectronic communication signal 26 to the appropriate communicationdevice 18 b.

[0033] The optic fiber communication system 14 may also include one ormore optical relays 30. The optical relay 30 operates to relay opticalcommunication signals 28 through the optic fiber 22. Optical relays 30are typically used when the length of optic fiber 22 is long and thequality of the optical communication signals 28 will degrade over theentire length of the optic fiber 22.

[0034] Conduit system 10 provides an environmentally secure protectiveshell that surrounds the optic fiber 22. As discussed previously, as aresult of the superior operating capabilities of optic fibercommunication systems 14, many wireline systems are being replaced withoptic fiber communication systems 14 and new lines are often installedusing optic fiber communication systems 14. Accordingly, thousands ofmiles of conduit systems 10 are being installed each year.

[0035] Conduit system 10 includes various sections of pipe, or conduits32, 34. Conduit couplings 12 form a transition between associatedsections of conduit, for example 32 and 34. Each conduit 32, 34typically includes a smooth, constant exterior diameter. The connectionbetween conduits 32, 34 and couplings 12 may be formed with mechanicalcouplings, adhesives, slip-fit, friction-fit, or electro-fusion, whereincouplings 12 and conduits 32, 34 are heated and melted together.Conduits 32, 34 may include innerduct, outerduct, or any combinationthereof. Typically, outerduct refers to a conduit which carries one ormore conduits or other medium therein. Innerduct refers to conduit andcouplings carried within the outerduct. The teachings of the presentinvention are applicable to both inner and outer-duct systems.

[0036] In practice, conduit system 10 may include any system providedfor protection of any medium carried therein. Furthermore, conduitsystem 10 may be specifically designed to carry any solid medium as wellas fluids, including liquids and gases. Conduit system 10 may maintainambient pressure, or include a pressurized medium, for example apressurized fire protection system for distributing water or fireresistant chemicals, or gases. In another embodiment, conduit system 30may be designed for gravity flow systems, including waste-waterdistribution and disposal systems.

[0037] Conduits 32 and 34, and therefore, clamshell coupling 12 may beprovided in a variety of different sizes, within the teachings of thepresent invention. For example only, and not by way of limitation, forapplications in which conduits 32 and 34 form innerduct, typical sizesinclude 1¼ inch, 1½ inch, and two inch diameter sections. Forapplications where conduits 32 and 34 serve as outerduct, typical sizesinclude four to twelve inch outer diameter sections.

[0038] Conduits 32, 34 and couplings 12 may include any type of pipegrade metal, plastic, or composite material. Examples include polyvinylchloride (PVC), high density polyethylene (HDPE), and glass filled HDPE.Various metal conduit materials are also available and include aluminum,copper, carbon-steel and other metal alloys.

[0039] One particular type of conduit coupling 12 suitable for joiningadjacent sections of conduit 32 and 34 is illustrated in more detail inFIG. 2A, and generally designated by the reference numeral 40. Clamshellcoupling 40 is one type of coupling which may be used to couple togetherand/or repair damaged sections of conduits 32 and/or 34, withouteffecting the installed optic fibers 22.

[0040] Coupling 40 includes a first longitudinal housing 50 a and asecond longitudinal housing 50 b. In the illustrated embodiment housings50 a and 50 b are corresponding mirrored images of one another. Forillustrative purposes, primarily longitudinal housing 50 a will bedescribed in detail, since much of longitudinal housing 50 b is hiddenfrom view. It will be recognized by those skilled in the art thatlongitudinal housings 50 a and 50 b need not contain identical, mirroredimage attributes, within the teachings of the present invention. A fewexamples of the many acceptable deviations from the configurations oflongitudinal housings 50 a and 50 b of FIG. 2A, will be described laterin more detail.

[0041] Longitudinal housings 50 a and 50 b are generally complementaryin that they fit together to form a circumferential collar surrounding aportion of outer diameters 33 and 35 of conduits 32 and 34,respectively. Longitudinal housings 50 a and 50 b may be coupledtogether at a first longitudinal joint 60 a and a second longitudinaljoint 60 b of housing 50 a. Clamshell coupling 40 may include analignment system that operates to align the longitudinal housings 50 aand 50 b. In the illustrated embodiment, the alignment system includes acomplementary pin 62 and boss 63 arrangement on a longitudinal housings50 a and 50 b. Each pin 62 has a corresponding boss 63 which engage eachother when longitudinal housings 50 a and 50 b are properly aligned forinstallation. It will be understood that the alignment system mayinclude other alignment devices without departing from the scope of thepresent invention.

[0042] Clamshell coupling 40 also includes a pair of identical slidablelocking mechanisms 88 and 89. Locking mechanisms 88 and 89 cooperatewith first and second longitudinal housings 50 a and 50 b to securehousings 50 a and 50 b together and/or to secure longitudinal housings50 a and 50 b around outer diameters 33 and 35 of conduits 32 and 34,respectively. Slidable locking mechanisms 88 and 89 need not beidentical in configuration and/or operation in order to securelongitudinal housings 50 a and 50 b, within the teachings of the presentinvention. For example, housings 50 a and 50 b may be assembled using ahinge and a single slidable locking mechanism 188, as illustrated inFIG. 3A.

[0043] Longitudinal membrane gaskets 66 a and 66 b may also be providedat each of first and second longitudinal joints 60 a and 60 b. Membranegaskets 66 a and 66 b generally include rubber-type seals disposedwithin grooves 44 a and 44 b, and cooperate to enhance a fluid-tightseal between longitudinal housings 50 a and 50 b, to prevent a breach ofthe seal between the interior of conduits 32 and 34 and ambientenvironment. In another embodiment, gaskets 66 a and 66 b may includeflat smooth surfaces molded into longitudinal joints 60 a and 60 b thatact as a seal between the clamshell coupling 40 and conduits 32 and 34.It will be understood that gaskets 66 a and 66 b may include othersuitable sealing devices without departing from the scope of the presentinvention. Many suitable alternatives exist capable of forming this sealbetween longitudinal housings 50 a and 50 b. For example, longitudinalhousings 50 a and 50 b may be treated with a liquid sealer, prior toassembly. In the embodiment illustrated in FIG. 2A, longitudinalmembrane gaskets 66 a and 66 b are formed of a buna material. Othersuitable materials, for example compressible metals, plastics, andcomposites may be used in the alternative. Gaskets 66 a and 66 b may beselected from a group of materials capable of maintaining their sealingproperties under adverse environmental conditions.

[0044] Longitudinal housings 50 a and 50 b may be fabricated from aplastic material that is semi-transparent. The semi-transparency oflongitudinal housings 50 a and 50 b allow a user to visually verify thatconduits 32 and 34 are adequately engaged to prevent a gap betweenconduits 32 and 34 which may cause an obstruction, or breach in conduitsystem 10. Additionally, a practitioner may view outer diameters 33 and35, as well as interior diameter 54 through clamshell coupling 40 toverify that no burrs or other obstructions are present which willjeopardize the fluid-tight seal and/or the integrity of the structuralcoupling between housings 50 a, 50 b and conduits 32 and 34. In theillustrated embodiment, components of clamshell coupling 40 may befabricated from an Acetal copolymer, or other high modulus plasticmaterial. Accordingly, coupling 40 includes the benefit of corrosion andchemical resistance, which extends the operating life of coupling 40.Other materials suitable for use in the fabrication of components ofconduit coupling 40 include plastics, such as rigid or plasticized PVC,polyethylene, and HDPE. Components of clamshell coupling 40 may also befabricated from various other plastics, metals, and composites, withinthe teachings of the present invention.

[0045] Longitudinal housing 50 a generally includes an elongate,semi-cylindrical, semi-tubular configuration, having an exteriordiameter 52, an interior diameter 54, and first and second ends 56 and58, respectively. Interior diameter 54 generally corresponds withexterior diameters 33 and 35 of conduits 32 and 34, respectively. Firstand second ends 56 and 58, of housings 50 a and 50 b are each adapted toreceive, and may be coupled with conduits 32 and 34. Exterior diameter52 includes an indented region 85 which extends from second end 58toward first end 56, terminating at a dead stop 87. Indented region 85forms a locking lug 86 along exterior diameter 52 which cooperates withslidable locking mechanism 88 to secure longitudinal housings 50 a and50 b, and slidable locking mechanism 88 together. It will be recognizedby those skilled in the art that indented region 85, lug 86 and slidablelocking mechanism 88 may include various configurations within theteachings of the present invention.

[0046] In order to assemble longitudinal housings 50 a and 50 b uponconduits 32 and 34 the following steps may be followed in almost anyorder. Gaskets 66 a and 66 b may be installed within their respectivegrooves 44 a and 44 b. Conduits 32 and 34 may be placed together inorder to form a continuous conduit with a single joint at the transitionbetween conduits 32 and 34. First longitudinal housing 50 a may beplaced along the outer diameters 33 and 35 of conduits 32 and 34,respectively, such that the transition between conduits 32 and 34 occursat the approximate longitudinal midpoint of longitudinal housing 50 a,within a central portion 57 of housing 50 a. Pins 62 and bosses 63 maybe used to align second longitudinal housing 50 b with longitudinalhousing 50 a such that longitudinal housing 50 b covers a portion ofouter diameters 33 and 35, and the transition between conduits 32 and 34occurs at the approximate longitudinal midpoint of longitudinal housing50 b. Slidable locking mechanisms 88 and 89 may then be installed tosecure clamshell coupling 40 upon conduits 32 and 34.

[0047] Slidable locking mechanism 88 includes first and secondprotrusions 100 and 102 which cooperate with locking lugs 86 of housings50 a and 50 b to secure slidable locking mechanism 88 in place. Afterassembling housings 50 a and 50 b, as described above, a first end 104of locking mechanism 88 may be installed at second end 58 of housing 50a. First protrusion 100 may be manipulated within indented region 85such that first protrusion 100 cooperates with locking lug 86 of housing50 a. Similarly, second protrusion 102 may be manipulated withinindented region 85 of housing 50 b such that second protrusion 102cooperates with locking lug 86 of housing 50 b to secure lockingmechanism 88. Locking mechanism 88 may then be slidably installed andforced toward first end 56, until first end 104 contacts dead stop 87.Alternatively, locking mechanism 88 may be snapped directly into placeover lugs 86, without having to slide locking mechanism 88.

[0048] Dead stops 87 prevent the lateral movement of mechanisms 88 and89, with respect to housings 50 a and 50 b beyond that required to forma suitable coupling therebetween. Dead stop 87 prevents lockingmechanism 88 from sliding too far toward first end 56. When properlyinstalled, first protrusion 100 and second protrusion 102 cooperate withlocking lugs 86 of housings 50 a and 50 b, respectively, to securelocking mechanism 88 in place, and to secure housings 50 a and 50 btogether at longitudinal joint 60 a. Slidable locking mechanism 89 maybe installed in a similar manner to secure locking mechanism 89 in placeadjacent second longitudinal joint 60 b, and to secure housings 50 a and50 b together at joint 60 b. One advantage to the use of lockingmechanism 88 and 89 includes an even distribution of force. For example,when a force is exerted upon locking mechanisms 88 or 89, or clamshellcoupling 40, the force is evenly distributed across seals 66 a and 66 b,along joints 60 a and 60 b. Prior art mechanical fasteners used tosecure longitudinal housings caused point loading along joints 60 a and60 b, which lead to failure and leaks.

[0049] Slidable locking mechanisms 88 and 89 may engage substantiallythe full length of the longitudinal locking lugs 86, and operate toclamp and secure longitudinal housings 50 a and 50 b to conduits 32 and34. Slidable locking mechanisms 88 and 89 include the advantage of asmall cross sectional profile that allows clamshell coupling 40 to bepulled through a restrictive passage with minimal difficulty. It will beunderstood that the coupling system 58 may comprise other suitablefastening devices without departing from the scope of the presentinvention. Suitable alternatives will be described later in more detail.

[0050] Longitudinal housings 50 a and 50 b generally include a chamfer96 on each end 56 and 58 which extend along longitudinal locking lugs86. Chamfer 96 allows clamshell coupling 40 to be pulled through theinstallation equipment without becoming snagged on the installationequipment or other materials. Chamfer 96 also allows clamshell coupling40 to be pulled through restrictive passages with less resistance thanconventional couplings. Furthermore, chamfer 96 allows lockingmechanisms 88 and 89 to be installed more easily, without sharp edges tosnag locking mechanisms 88 and 89 during installation.

[0051] In practice, longitudinal housings 50 a and 50 b may be initiallysecured together over conduits 32 and 34 using a wrench (not expresslyshown). Using the wrench, slidable locking mechanisms 88 and 89 sliderelatively easily over longitudinal locking lugs 86. If a wrench is notavailable, slidable locking mechanisms 88 and 89 may be hammered intoplace without substantial damage to locking mechanisms 88 or 89, orlongitudinal locking lugs 86. Slidable locking mechanisms 88 and 89 mayalso include detents 98 that allow a tool to be inserted into thedetents 98 and used to forcibly slide locking mechanisms 88 and 89 intoposition over longitudinal locking lugs 86. Installation of lockingmechanisms 88 and 89 forces longitudinal housings 50 a and 50 b andtheir associated restraint systems (to be described later, in moredetail) to actively engage conduits 32 and 34. Conduits 32 and 34 aresecured within clamshell coupling 40 and will resist being dislodgedfrom clamshell coupling 40 under very high longitudinal tensile loads orrotational loads.

[0052] Interior diameter 54 is generally uniform and smooth along theentire longitudinal length of housing 50 a, between first end 56 andsecond end 58. Longitudinal housing 50 a also includes a number ofrestraint systems at interior diameter 54 which enhance the seal betweencoupling 40 and conduits 32 and 34, and increase the strength of theconnections therebetween. The restraint systems actively engage conduits32 and 34 to prevent conduits 32 and 34 from becoming disengaged fromclamshell coupling 40.

[0053] Referring to FIGS. 2A-2C, restraint systems associated withinterior diameter 54 may include semi-circular inserts 70 of teeth 72,circular ribs 64, and/or semi-circular gaskets 68. First end 56 ofhousing 50 a includes a notched opening 67 operable to recess asemi-circular gasket 68. Similarly, second end 58 includes a secondnotched opening 67 to receive a second gasket 68. Corresponding notchedopenings 67 and gaskets 68 may also be located at each of first andsecond ends 56 and 58 of housing 50 b. Semi-circular gaskets 68 enhancethe fluid-tight seal formed between conduits 32 and 34, and longitudinalhousings 50 a and 50 b. Each gasket 68 is appropriately sized toprotrude from its respective notched opening 67, an appropriate amountto form a friction fit between the outer diameters 33 and 35 of conduits32 and 34, and clamshell coupling 40. The friction fit enhances thefluid-tight seal, and provides additional strength to the connection toprevent the inadvertent separation or coupling 40 from conduits 32 and34. When properly assembled, each gasket 68 of housing 50 a contacts andcooperates with a corresponding gasket 68, associated with housing 50 bto form a continuous cylindrical, tubular, fluid-tight seal. Gasket 68may be provided along interior diameter 54 of housings 50 a and 50 b.Gasket 68 may be compressed between exterior diameters 33 and 35 ofconduits 32 and 34, respectively, and interior diameter 54, in order toinsure a proper seal between conduits 32 and 34, and clamshell coupling40. This prevents any media contained within conduits 32 and 34 fromescaping to the ambient environment, and also prevents ambientcontaminates from entering conduit system 30. A proper seal betweenconduits 32 and 34, and clamshell coupling 40 may be beneficial for anyapplication requiring pressure differentials between the interior ofconduits 32 and 34 and ambient environment. For example, in order toinstall fiber optic cables within conduits 32 and 34, conduits 32 and 34may be pressurized as fiber optic cables are “blown” through conduits 32and 34.

[0054] Materials used to fabricate gasket 68 may be selected accordingto specific criteria, including their resistance to chemical andultraviolet exposure. In the illustrated embodiment, gasket 68 may befabricated from silicon. Many other materials may be used to fabricategasket 68, including various elastomeric and/or compressible materials.

[0055] The number, size, shape and configuration of notched openings 67and gaskets 68 may be significantly modified within the teachings of thepresent invention. For example, additional notched openings andcorresponding gaskets may be located adjacent first end 56, second end58, or within central portion 57, as desired. In another application,gaskets could be attached to outer diameters 33 and 35 of conduits 32and 34, prior to installation of clamshell coupling 40. Alternatively,gaskets could be pre-installed upon or attached to interior diameter 54prior to assembly of coupling 40. In either case, notched openings 67would not necessarily be required. For example, gasket 68 could beattached to housing 50 a with an adhesive, or mechanical connectors.

[0056] In yet another embodiment, gasket 68 could be molded withininterior diameter 54 during the molding process. In this embodiment,gasket 68 may be formed of material similar to housing 58, or any othermaterial described within this specification. In this embodiment, gasket68 may function similar to circular ribs 64, which are described in moredetail below.

[0057] Interior diameter 54 also includes a plurality of circular ribs64. In the illustrated embodiment, central portion 57 separates a totalof three circular ribs at first end 56 of housing 50 a, and threecircular ribs at second end 58 of housing 50 a. Housing 50 b includes asimilar configuration of circular ribs 64. The number, size, shape andconfiguration of ribs 64 may be significantly modified within theteachings of the present invention.

[0058] The plurality of circular ribs 64 enhance the strength of theconnection between conduits 32 and 34 and longitudinal housing 50 a.Circular ribs 64 each include teeth 80 which form sharp points 81 whichare operable to effectively engage conduits 32 and 34. Each tooth 80 isconfigured to have a front face 82 which forms a greater angle withrespect to an axis Y, drawn through the base of each tooth 80, than doesits rear face 83. In the illustrated embodiment, rear face 83 extendsgenerally perpendicular to axis Y. Conversely, front face 82 extends atan angle β with respect to axis Y. In one embodiment, β may be betweenfive and forty-five degrees, for example, approximately equal to 30degrees. In this type of application, sharp point 81 and theconfiguration of front face 82 and rear face 83 allow a tighter grip ofclamshell coupling 40 upon conduits 32 and 34.

[0059] In the illustrated embodiment of FIG. 2B, first end 56 includes aplurality of semi-circular ribs 64 which extend along a planeapproximately perpendicular to central axis X. Axis Y may be parallel toaxis X. In another embodiment, axis Y may be at an offset to axis X.Alternatively, ribs 64 may be configured to form a single continuousthread along a portion of, or the entirety of interior diameter 54 atfirst end 56. In another embodiment a continuous thread could extend anyportion of, or the entirety of interior diameter 54 between first end 56and second end 58.

[0060] As previously discussed, circular ribs 64 disposed along interiordiameter 54 include teeth 80. In this manner, in their respectiveassembled positions, first longitudinal housing 50 a and secondlongitudinal housing 50 b form a friction fit with conduit 32, and teeth80 which may function to bite or grab conduit 32, prevent the decouplingof clamshell coupling 40 from conduits 32 and 34. Once assembled,clamshell coupling 40 may also be press-fit upon conduit 32 and/or 34,and/or a press-fit type connection may be used to enhance the couplingbetween clamshell coupling 40 and conduit 32 and/or 34 after clamshellcoupling 40 is assembled upon conduit 32 and/or 34.

[0061] Teeth 80 at first end 56 generally point toward central portion57. Similarly, teeth 80 at second end 58 point towards central portion57. This orientation prevents conduits 32 and 34 from sliding towardfirst end 56 and second end 58, respectively. In another embodiment,circular ribs could be configured differently, with smooth, roundededges for example, within the teachings of the present invention.

[0062] In the illustrated embodiment, ribs 64 are formed within interiordiameter 54 during the molding process. Alternatively, notched openingscould be molded into interior diameter 54 during the molding process andribs 64 could be independently press-fit into interior diameter 54 priorto assembly of coupling 40, similar to inserts 70, which are describedbelow.

[0063] Interior diameter 54 also includes a plurality of notchedopenings 71 operable to recess and secure a plurality of semi-circularinserts 70. In one embodiment, notched openings 71 may be formed withininterior diameter 54 during the molding process. In the same embodiment,inserts 70 may be “pre-fit” within notched openings 71 prior to assemblyof clamshell coupling 40. In the illustrated embodiment, three inserts70 are located at first end 56 of housing 50 a and three inserts 70 arelocated at second end 58 of housing 50 a. Similarly, three inserts 70are located at each end 56 and 58 of housing 50 b. The number, size,shape and configuration of inserts 70 may be significantly modified,within the teachings of the present invention.

[0064] Inserts 70 include a row of gripping teeth 72, configured tocooperate with exterior diameters 33 and 35 of conduits 32 and 34,respectively, to hold conduits 32 and 34 securely in place withincoupling 40. Gripping teeth 72 may be provided of various sizes withinthe same coupling 40, as illustrated in FIG. 2C. Each tooth 72culminates in a point 73 which extends from interior diameter 54 towardcentral axis X. As best shown in FIG. 2C, teeth 72 may be configuredsuch that points 73 extend approximately perpendicular to central axialaxis Z-Z. This configuration prevents axial rotation of conduits 32 and34 within coupling 40. In another embodiment, teeth 72 may be configuredsuch that all points 73 extend toward an imaginary midpoint M.

[0065] Inserts 70, teeth 72 and points 73 are also configured such thatpoints 73 extend toward central portion 57 of interior diameter 54. Forexample, teeth 72 may extend toward central portion 57 such that teeth72 form an angle ∝ with respect to axis Y. ∝ may be between five andforty-five degrees, for example thirty degrees. Accordingly, teeth 72engage conduits 32 and 34 to prevent the decoupling of conduits 32 and34, and coupling 40.

[0066] In particular, teeth 72 and points 73 operate by penetratingouter diameters 33 and 35 of conduits 32 and 34, respectively. Teeth 72may penetrate approximately 25-75% into the wall of conduits 32 and 34.Similarly, teeth 80 may be configured such that they penetrateapproximately 25-75% into the walls of conduits 32 and 34. This preventsconduits 32 and 34 from separating from clamshell coupling 40 under veryhigh longitudinal tension loads. Some embodiments of clamshell coupling40 may withstand a larger longitudinal tensile load than conduits 32 and34. In other words, when being pulled apart, conduits 32 and/or 34 mayfracture under a tensile load without conduits 32 and 34 being pulledout of clamshell coupling 40. This type of connection may also operateto resist a rotational load between conduits 32 and 34 and clamshellcoupling 40.

[0067] Inserts 70 may be generally arranged in concentric rows alonginterior diameter 54. In the illustrated embodiment of FIGS. 2A-2C,inserts 70 have a generally semicircular shape with individual teeth 72formed on the internal diameter of the insert 70. In another embodimentto be discussed with respect to FIG. 3A, the inserts 70 may have thegeneral shape of conical spikes. Inserts 70 may be integrally moldedinto interior diameter 54, assembled separately into correspondingcavities within interior diameter 54, or otherwise suitably secured tointerior diameter 54. Inserts 70 may also be fabricated from anyplastic, metal or composite material.

[0068] Clamshell coupling 40 may also be used to repair damage to anyparticular conduit, for example conduit 32, without damaging opticfibers 22 contained within conduit 32. Clamshell coupling 40 may beinstalled over a damaged portion of conduit 32 in a similar manner asdescribed above. Clamshell coupling 40 forms a seal around the damagedportion of conduit 32, and also structurally strengthens conduit 32 toprevent further damage.

[0069]FIG. 3A is an orthographic drawing of a clamshell coupling 140 inaccordance with another embodiment of the present invention. Clamshellcoupling 140 may be used in a similar manner to coupling 40, describedabove. In this embodiment, a hinge mechanism 200 may form a couplingbetween longitudinal housings 50 a and 50 b, and may comprise a thinmembrane that connects the longitudinal housings 50 a and 50 b. It willbe understood that hinge mechanism 200 may comprise other suitablemechanisms without departing from the scope of the present invention.

[0070] Hinge mechanism 200 forms an at least partially fluid-tight sealbetween housings 150 a and 150 b at a longitudinal joint 160 b. Alongitudinal membrane gasket 166 a may be recessed within groove 144 aprior to assembly of clamshell coupling 140. Gasket 166 a enhances thefluid-tight seal between housings 150 a and 150 b at longitudinal joint160 a. In an alternative embodiment, a gasket may also be provided atlongitudinal joint 160 b. Only a single slidable locking mechanism 188is necessary to firmly and securely couple housings 150 a and 150 b intheir respective installed positions. Locking mechanism 188 may alsoinclude first and second protrusions 202 and 204, and detents 198, allof which function similarly to their corresponding components of FIGS.2A-2C.

[0071] Clamshell coupling 140 also includes a number of restraintsystems at its interior diameter 154. Interior diameter 154 includesnotched openings 167 and gaskets 168, which function similarly to theircorresponding components of clamshell coupling 40 of FIGS. 2A-2C.Instead of circular ribs 64 and inserts 70, as illustrated in FIG. 2B,clamshell coupling 140 includes a plurality of spikes 170 which enhancethe coupling between conduits 32 and 34, and clamshell coupling 140.

[0072] Spikes 170 may be arranged within interior diameter in a patternwhich will maximize the strength of the coupling between clamshellcoupling 140 and conduits 32 and 34. One possible configuration ofspikes 170 within interior diameter 154 is illustrated in FIG. 3A. Itwill be recognized by those skilled in the art that the number, size,configuration, type and layout of spikes 170 within interior diameter154 may be significantly modified within the teachings of the presentinvention. For example, spikes 170 may be laid out to form concentriccircles within interior diameter 154 in a similar manner as inserts 70and teeth 72 are arranged in FIG. 2B.

[0073] For illustrative purposes, an enlarged spike 170 is illustratedin more detail in FIG. 3B. In the illustrated embodiment, spikes 170 aregenerally conical. In another embodiment, spikes 170 may be provided orvarious shapes and sizes. Any protrusion which extends from interiordiameter 154 and operable to engage a section or conduit when clamshellcoupling 140 is in an assembled position is suitable for use within theteaching of the present invention. Spike 170 may include a threaded stem171 which provides a means to secure spike 170 within interior diameter154. Accordingly, interior diameter 154 may include a plurality ofcorresponding openings 172. Spikes 170 may be threaded into openings172. Openings 172 may be pre-threaded to accept threaded stem 171.Alternatively, threaded stem 171 may be provided of the “self-tapping”type to allow simplified installation of spikes 170 within openings 172.In this embodiment, openings 172 need not necessarily includecorresponding threads.

[0074] In still another embodiment, openings 172 may be providedapproximately the same diameter as threaded stem 171. In thisembodiment, spikes 170 may be press-fit into openings 172.Alternatively, spikes 170 may be incorporated into interior diameter 154during the molding process, eliminating the necessity to install spikes170 after fabrication of housings 150 a and 150 b.

[0075]FIG. 4 is an orthographic drawing of a clamshell coupling 240 inaccordance with another embodiment of the present invention. Clamshellcoupling 240 may function similarly to clamshell coupling 40 of FIGS.2A-2C. Clamshell coupling 240 includes a single longitudinal housing 250and a tension coupling system 204. Longitudinal housing 250 includes agenerally cylindrical, generally tubular configuration. Housing 250 maybe fabricated from a flexible material as described with regard toclamshell coupling 40. A longitudinal gap 206 within housing 250 allowslongitudinal housing 250 to be installed around exterior diameters 33and 35 of conduits 32 and 34, respectively. When longitudinal housing250 is installed over conduits 32 and 34, tension coupling system 204may be tightened to clamp housing 250 securely around conduits 32 and34.

[0076] Tension coupling system 204 comprises a number of tension straps205 that circumferentially surround the single piece longitudinalhousing 250 that can be tightened to secure the clamshell coupling 240to conduits 32 and 34. In practice, clamshell coupling 240 may beparticularly suited for repairing minor damage in conduits 32 and 34.

[0077] As illustrated in FIG. 4, clamshell coupling 240 may include aplurality of circular ribs 264. Ribs 264 are configured similar to andfunction similar to ribs 64 of clamshell coupling 40. Ribs 264 mayextend along the entire interior diameter 254, to enhance thefluid-tight seal between conduits 32 and 34, and clamshell coupling 240.When properly installed, gap 206 may partially or totally close, suchthat longitudinal surface 260 contacts longitudinal surface 262.Clamshell coupling 240 may also incorporate chamfer 296 which isconfigured similarly to and functions similarly to chamfer 96 ofclamshell coupling 40 (see FIG. 2A).

[0078] Interior diameter 254 may also incorporate inserts 70, spikes 170and/or gaskets 68, as described previously within this specification. Itwill be recognized by those skilled in the art that the variousconfigurations of clamshell couplings 40, 140 and 240 may incorporateany of the various features described with respect to one another,including pins, bosses, circular ribs, gaskets, inserts, teeth, slidablelocking mechanisms, hinges and locking lugs. In addition, regardingconfigurations which incorporate two housings, each housing mayincorporate one or all of these features without regard to the featurespresent on the corresponding housings.

[0079] The clamshell couplings described above provide significantadvantages. The quality of the seals formed between housings andconduits reduce costs spent troubleshooting leaks. In addition, thereduced size, weight and profile of the couplings enhances theirmaneuverability during installation, particularly in confined spaces.The reduced size and profile also causes reduced friction duringinstallation of conduits, particularly when conduits are pulled througha bore hole. Furthermore, assembly of the couplings is simplified incontrast to prior couplings which utilize bolted and/or threadedconnections.

[0080] Although the present invention has been described in severalembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present invention encompasssuch changes and modifications that fall within the scope of theappended claims.

What is claimed is:
 1. A conduit coupling, comprising: a first,semi-tubular housing having a first interior diameter, a first exteriordiameter and first and second ends; the first and second ends adapted toreceive at least one section of conduit; the first housing having atleast a first indented region forming a first locking lug upon the firstexterior diameter; a second semi-tubular housing complementary to thefirst housing, the second housing having a second interior diameter anda second exterior diameter; the second housing having at least a secondindented region forming a second locking lug upon the second exteriordiameter; and a first locking mechanism having first and secondprotrusions which cooperate with the first and second locking lugs tocouple the first and second housings at a first longitudinal joint. 2.The conduit coupling of claim 1, further comprising a hinge operable tocouple the first and second housings at a second longitudinal joint. 3.The conduit coupling of claim 1, further comprising: a third indentedregion associated with the first housing, forming a third locking lug onthe first exterior diameter; a fourth indented region associated withthe second housing, forming a fourth locking lug on the second exteriordiameter; and a second locking mechanism having third and fourthprotrusions which cooperate with the third and fourth locking lugs,respectively, to couple the first and second housings at a secondlongitudinal joint.
 4. The conduit coupling of claim 1, furthercomprising at least one semi-circular rib disposed upon the firstinterior diameter.
 5. The conduit coupling of claim 4, wherein the atleast one semi-circular rib further comprises: a front face and a rearface forming a sharp point of a tooth, the tooth extending toward acentral portion of the coupling; the rear face approximatelyperpendicular to a longitudinal central axis of the coupling; and thefront face oriented at an angle between five and forty-five degrees withrespect to the longitudinal central axis.
 6. The conduit coupling ofclaim 1, further comprising at least one semi-circular insert disposedalong the first interior diameter, the insert including a plurality ofgripping teeth operable to engage the at least one section of conduit,when the conduit coupling is in an assembled position.
 7. The conduitcoupling of claim 6, wherein the gripping teeth extend toward a centralportion of the conduit coupling, and form an angle between five andfortyfive degrees with respect to a longitudinal central axis of theconduit coupling.
 8. The conduit coupling of claim 6, wherein thegripping teeth each include a respective point which extendsperpendicular to an axial central axis of the conduit coupling.
 9. Theconduit coupling of claim 6, wherein the gripping teeth each include arespective point which extends toward an axial midpoint of the conduitcoupling.
 10. The conduit coupling of claim 1, further comprising aplurality of spikes extending from the first interior diameter andoperable to engage the at least one conduit when the conduit coupling isin an assembled position.
 11. The conduit coupling of claim 10, whereinthe spikes extend toward a central portion of the conduit coupling, andform an angle between five and forty-five degrees with respect to alongitudinal cental axis of the conduit coupling.
 12. The clamshellcoupling of claim 10, wherein the spikes each include a respective pointwhich extends approximately perpendicular to an axial central axis ofthe conduit coupling.
 13. The conduit coupling of claim 10, wherein thespikes each include a respective point which extends toward an axialmidpoint of the conduit coupling.
 14. The conduit coupling of claim 1,further comprising at least one longitudinal seal disposed along thefirst longitudinal joint.
 15. A conduit coupling, comprising: a firstlongitudinal housing having a first interior diameter; a secondlongitudinal housing, complementary to the first longitudinal housingand operable to be coupled with the first longitudinal housing forinstallation upon at least a first conduit; and the first longitudinalhousing including at least one restraint system disposed upon the firstinterior diameter.
 16. The conduit coupling of claim 16, wherein therestraint system includes at least one semi-circular rib, comprising: afront face and a rear face forming a sharp point of a tooth, the toothextending toward a central portion of the coupling; the rear faceapproximately perpendicular to a longitudinal central axis of thecoupling; and the front face oriented at an angle between five andforty-five degrees with respect to the longitudinal central axis. 17.The conduit coupling of claim 15, wherein the restraint system comprisesat least one semi-circular insert disposed along the first interiordiameter, the insert including a plurality of gripping teeth operable toengage the sections of conduit when the conduit coupling is in anassembled position.
 18. The conduit coupling of claim 17, wherein thegripping teeth extend toward a central portion of the conduit coupling,and form an angle between five and forty-five degrees with respect to alongitudinal central axis of the conduit coupling.
 19. The conduitcoupling of claim 17, wherein the gripping teeth each include arespective point which extends perpendicular to an axial central axis ofthe conduit coupling.
 20. The conduit coupling of claim 17, wherein thegripping teeth each include a respective point which extends toward anaxial midpoint of the conduit coupling.
 21. The conduit coupling ofclaim 15, wherein the restraint system further comprises a plurality ofspikes extending from the first interior diameter and operable to engagethe first conduit when the conduit coupling is in an assembled position.22. The conduit coupling of claim 21, wherein the spikes extend toward acentral portion of the conduit coupling, and form an angle between fiveand forty-five degrees with respect to a longitudinal cental axis of theconduit coupling.
 23. The clamshell coupling of claim 21, wherein thespikes each include a respective point which extends approximatelyperpendicular to an axial central axis of the conduit coupling.
 24. Theconduit coupling of claim 21, wherein the spikes each include arespective point which extends toward an axial midpoint of the conduitcoupling.
 25. The conduit coupling of claim 15, wherein the restraintsystem comprises at least one semi-circular gasket protruding from anotched opening within the first interior diameter.
 26. A conduitcoupling, comprising: a semi-cylindrical, semi-tubular housing having aninterior diameter and an exterior diameter, the housing including alongitudinal gap disposed between adjacent first and second longitudinalsurfaces of the housing; at least one tension strap disposed around theexterior diameter of the conduit coupling, and operable to couple theconduit coupling with at least a first section of conduit wherebytightening the strap reduces the size of the longitudinal gap.
 27. Theconduit coupling of claim 26, further comprising at least one restraintsystem disposed upon the interior diameter of the conduit coupling.